Physics

Magnetism and Electromagnetism

1,019 Questions

This hub provides practice questions on magnetism and electromagnetism. It covers magnetic flux density, electromagnets, magnetic lines of force, and electromagnetic induction. These physics concepts frequently appear in technical and non-technical competitive exams.

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Magnetism and Electromagnetism Questions

Multiple choice physics magnetic effect of electric current fleming's left hand rule magnetic force magnetic force on a moving charge and current carrying wire

A positive charge is at rest in a uniform magnetic field directed to the right. What force does the positive charge feel, due to the magnetic field?

  1. An upward force.

  2. A downward force.

  3. A force to the left.

  4. No force is felt.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
For experiencing a magnetic force on a charge  particle, the particle should move in the magnetic field with some velocity. As the velocity of the particle is zero so, the force on the particle is also zero.
Multiple choice physics magnetic effect of electric current fleming's left hand rule magnetic force magnetic force on a moving charge and current carrying wire

The direction of force on a current carrying conductor placed in a magnetic field is given by :

  1. Fleming's Left Hand Rule

  2. Fleming's Right Hand Rule

  3. End Rule

  4. Right Hand Palm Rule
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The direction of this force is always right angles to the plane containing both the conductor and the magnetic field, and is predicted by Fleming’s Left-Hand Rule.

Multiple choice physics magnetic effect of electric current fleming's left hand rule magnetic force magnetic force on a moving charge and current carrying wire

How will be the direction of force will get changed, if the current is reversed in the conductor placed in a magnetic field?

  1. Direction of force rotates by right angle

  2. Direction of force is reversed.

  3. Direction of force remains same

  4. Can't say
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The magnetic force on a current-carrying conductor is given by F = I(L x B). If the direction of the current (I) is reversed, the direction of the resulting force (F) is also reversed.

Multiple choice physics magnetic effect of electric current fleming's left hand rule magnetic force magnetic force on a moving charge and current carrying wire

Which rule determines the direction of force experienced by a current Carrying straight conductor placed in a magnetic field which is perpendicular to it.

  1. Maxwell right hand grip rule

  2. Fleming's left hand rule

  3. Fleming's right hand rule

  4. None
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

We considered the direction of the current and that of the magnetic field perpendicular to each other and found that the force is perpendicular to both of them. The three directions can be illustrated through a simple rule, called Flemings left-hand rule. According to this rule, stretch the thumb, forefinger and middle finger of your left hand such that they are mutually perpendicular. If the first finger points in the direction of magnetic field and the second finger in the direction of the current, then the thumb will point in the direction of motion or the force acting on the conductor.

Multiple choice physics magnetic effect of electric current fleming's left hand rule magnetic force magnetic force on a moving charge and current carrying wire

In the statement of Fleming's left hand rule, magnetic field is represented by

  1. thumb

  2. fore finger

  3. middle finger

  4. none
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The direction of the current and that of the magnetic field perpendicular to each other and found that the force is perpendicular to both of them. The three directions can be illustrated through a simple rule, called Flemings left-hand rule. According to this rule, stretch the thumb, forefinger and middle finger of your left hand such that they are mutually perpendicular. If the first finger points in the direction of magnetic field and the second finger in the direction of the current, then the thumb will point in the direction of motion or the force acting on the conductor.

Multiple choice physics magnetic effect of electric current fleming's left hand rule magnetic force magnetic force on a moving charge and current carrying wire

In the statement of Fleming's left hand rule, what do the direction of centre finger represents

  1. motion

  2. magnetic field

  3. current

  4. none
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The direction of the current and that of the magnetic field perpendicular to each other and found that the force is perpendicular to both of them. The three directions can be illustrated through a simple rule, called Flemings left-hand rule. According to this rule, stretch the thumb, forefinger and middle finger of your left hand such that they are mutually perpendicular. If the first finger points in the direction of magnetic field and the second finger in the direction of the current, then the thumb will point in the direction of motion or the force acting on the conductor.

Multiple choice physics magnetism and matter paramagnetic material classification of magnetic material magnetism

A paramagnetic liquid is taken in a U-tube and arranged so that one of its limbs is kept between pole pieces of the magnet. The liquid level in the limb is

  1. goes down

  2. rises up

  3. remains same

  4. first goes down and then rise
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

When a paramagnetic liquid is taken in U-tube and one arm is placed between the poles of strong magnet, the liquid is feebly attracted by the magnet. Therefore, the level of the solution in the arm rises.

Multiple choice physics magnetism and matter paramagnetic material classification of magnetic material magnetism

Assertion : Paramagnetic substances get weakly attracted to a magnet.
Reason : They have tendency to move from a region of strong magnetic field to weak magnetic field

  1. If both assertion and reason are true and reason is the correct explanation of assertion.

  2. If both assertion and reason are true and reason is not the correct explanation of assertion.

  3. If assertion is true but reason is false.

  4. If both assertion and reason are false
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Paramagnetic substances have tendency to move from a region of weak magnetic field to strong magnetic field i.e., they get weakly attracted to a magnet.

Multiple choice physics magnetism and matter paramagnetic material classification of magnetic material magnetism

Consider the following statements I and II.
(I) Paramagnetism is explained by domain theory 
(II) Susceptibility of a diamagnetic substance is independent of temperature.
Identify the correct choice from the following. 

  1. Both I and II are correct

  2. Both I and II are incorrect

  3. I is correct and II is incorrect.

  4. I is incorrect and II is correct
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Paramagnetism is explained by the alignment of atomic magnetic moments, not domain theory, which applies to ferromagnetism. The magnetic susceptibility of diamagnetic substances is indeed independent of temperature.

Multiple choice physics magnetism and matter paramagnetic material classification of magnetic material magnetism

Assertion(A) : Earth's magnetic field inside a closed iron box is less as compared to the outside.
Reason(R) : The magnetic permeability of iron is low.

  1. Both A, R are true and R is the correct explanation of A

  2. Both A, R are true and R is not correct explanation of A

  3. A is true R is false

  4. A is false R is true
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The Earth's magnetic field inside a closed iron box is reduced due to magnetic shielding, which occurs because iron has high magnetic permeability, not low. Therefore, the assertion is true but the reason is false.

Multiple choice physics magnetism and matter paramagnetic material classification of magnetic material magnetism

The meniscus of a liquid contained in one of the limbs of a narrow U-tube is held electromagnet with the meniscus in line with the field. The liquid is seen to rise. This indicates that the liquid is

  1. anti-ferromagnetic

  2. paramagnetic

  3. diamagnetic

  4. non-magnetic
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Paramagnetic liquid tends to flow from region of weaker magnetic fields to stronger magnetic fields..

Multiple choice physics magnetism and matter paramagnetic material classification of magnetic material magnetism

The purpose of soft iron cylinder between the pole pieces of the horse-shoe magnet in a moving coil galvanometer is 

  1. to increase the magnetic induction in the polar

    gap

  2. to evenly distribute the magnetic lines of force

  3. to provide a radial magnetic field

  4. to reduce the magnetic flux leakage in the polar

    gap
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Soft iron cylinder is placed between the pole pieces of the horse-shoe magnet in a moving coil galvanometer to increase the magnetic induction in the polar gap. Soft iron is paramagnetic which increases magnetic induction when placed in field because atoms in soft iron align in such manner that it increases field.